Turbine-wheel.



M. E. THOMPSON.

TURBINE WHEEL. APPLICATION FILED JULY 2,1912.

1,108,945, Patented Sept. 1, 1914.

MILTO rnomrson, or ninGwAY, rENNsYLvANIA.

TURBINE-WHEEL.

Specification of Letters Patent.

Patented Sept. 1, 1914,

Application med July 2, 1912. Serial No. 707,173.

To all whom it may concern:

Be it known that: I, MILTON E. THOMP- soN, a citizen of the United States, and a resident of Ridgway, Elk county, State of Pennsylvania, have invented certain new and useful Improvements in Turbine- Wheels, of which the following is a specification.

My invention relates to -:turbine wheels such as are used in various types of steam turbines. Each of the wheels of these turbines carries a large number of blades or buckets projecting radially at the outer part The ordinary steam turbineof the wheel. of any substantial size has thousands of these buckets or blades each of which must be firmly held in position despite the high speed of rotation of the turbine wheel of which each forms a part and despite the machining themfrom a solid disk so as to produce an integral turbine wheel. The ex- I pense of such procedure is enormous, wh1le, 1

moreover, producing a Wheel which becomes wholly useless it but a single blade isiHllired. On the other hand, the more usual practice has been to manufactureturbine blades independently of the central portion of the turbine wheel and then secure each blade in position on the supporting portion of the wheel. Many specific means have been employed to this end, but they are all, so far as I have knowledge of them, faulty in one or more of the following respects, namely, in being too expensive to be practicable, remembering that a very small extra cost per blade means a greatly increased cost of the finished turbine with its thousands of blades; in producing a structure with weak spots here and there in the structure, as is the case where turbine blades'with dove-tail shanks are fitted into a dove-tail peripheral groove; in making it impossible to use blades of substantially the same width as the turbine wheel or in making it impossible to use blades that can'be,

strong and reliable means for attachment.

My invention consists in a means for constructing the turbine wheel and fastening the blades in place which will be economical and simple in construction and yet avoid the various defects in prior construction which I have above set out.

My invention will be more fully understood from the description hereinafter of the specific form of my invention illustrated in the drawings, it being understood that while I have illustrated in exact detail one specific form of my invention, my invention is broader than such specific embodiment thereofherein illustrated and described as will appear from the appended claims.

Referrin to the drawings Figure 1 illus trates part y in section and partly in side elevation a portion of a turbine wheel constructed in accordance with my invention; Fig. 2 is a section through the center of the portion of the wheel shown in Fig. 1; Fig. 3 shows four separate views of one of the turbine blades or buckets after it has'been machined-to proper form to be secured in place .on the supporting disk, and Fig. 4 shows three views of the distance pieces which are secured in place between the blades Blades 1 are preferably produced by cutting suitable lengths ;Eroma-rolled or drawn bar of the crescent shaped cross-section indicated in Fig. 3. Each bucket is shown as having a circular projection 2 at the top adapted to receive a bafiler which is, however, not illustrated in the drawings as it vforms no part of my present invention, as

any suitable bafiler may be used. The lower portion of the bucket has its wings 'cut away as indicated by the lines 3-3 in Fig. 3 to produce a central shank portion 4 having sides curved similarly to corresponding sides of the blades .The supporting wheel 5 for the bladeshas a central peripheral groove 6 to. receive the shanks 4 of the turbine blades. The walls. at the side of the groove'are of substantially the same thickness as the cut away portions'of the blades so that the blade and projection above the supporting wheel may be of substantially the same thickness as the wall. It is to be noted that the walls of the groove 8 are parallel. straight walls to permit the shanks of the blades to be inserted therein or removed. therefrom by blades; and in not providing a suflioiently.

movement of the blades in a radial direction inwardly or outwardly, thus enabling each blade to be independently inserted' or removed from the groove without afiectlng the position of the other blades. Betwe en each blade shank is a distance piece 7 of the formshownin Fig. 4, these distance pieces filling the space between adja' completel cent shan s. The blades and distance pieces are held in position and from'upward move ment by the rivets 8 which I prefer to arrange as shown, that is, with each rivet engaging a recess in a blade shank and a distance piece. These recesses or grooves in the distance pieces and shanks may. either be produced before these parts are inserted in the supportingdiskj orthe blades and distance pieces may first be put into place around the wheel "or a portion of the wheel and :holes for the rivets drilled through the Walls of the groove and partly in the distance pieces and partly in the blade shanks.

If any blade proves to be defective it can be removed by simply removing'two or three rivets and then slipping item; of the groove without disturbing any of the other blades of the wheel. A new blade can then be inserted'and riveted in place.

Having fully described my invention, What I claim as new and desire to protect by Letters Patent is:

1. A turbine wheel having a continuous peripheral groove with straight parallel .walls, blades-of: uniformcross-section but with the wings cut away at one end to form a central shank, said shanks fittingin said groove, distance pieces in the groove filling the spaces between said shanks, and rivets passing transversely through the wheel each rivet engaging a blade shank and distance piece.

2. A turbine wheel having a peripheral grooveyturbine blades of uniform cross-section except that their wings .are cut away at the base to form central shanks fitting said groove, said shanks being insertible in said groove 'by movement in a radial direction, and distance pieces similarly insertible in said groove, said blades and distance pieces being riveted in'said groove.

3. A turbine wheelzhaving a peripheral groove, turbine blades of substantially the same width as the wheel and of uniform 4. A turbine wheel having a peripheral groove, turbine blades of uniform cross-section except that their wings are cut away at the base to form centralshanks fitting said groove, said shanks being insertible in said groove by movement in a'firadial direction, distance pieces between said blades similarly insertible in said groove, and rivets, each engaging a blade and a distance piece securing the same together.

In testimonywhereof, I have signed my name to this specification, in the presence of two subscribing witnesses.

MILTON E. THOMPSON. Witnesses:

RICHARD EYRE, EDWIN SEGER. 

